Cross-presentation of lactoferrin encapsulated into chitosan-based nanoparticles

Area of Science:

• Immunology
• Nanotechnology
• Vaccine Development

Background:

• CD8+ cytotoxic T-cell responses are crucial for fighting intracellular pathogens.
• Major histocompatibility complex class I (MHCI) pathway is key for antigen presentation.
• Cross-presentation (CP) of soluble antigens is less efficient for T-cell activation.

Purpose of the Study:

• To investigate how encapsulating lactoferrin into polysaccharide nanoparticles (NPs) with varying properties affects antigen cross-presentation.
• To determine the impact of NP physicochemical properties on CD8+ versus CD4+ T-cell activation.

Main Methods:

• Lactoferrin (L) was encapsulated into five types of polysaccharide NPs with different sizes, charges, and hydrophobicity.
• Antibody subclasses (IgG2a for CD8+, IgG1 for CD4+) were measured to assess T-cell activation.
• Confocal microscopy was used to track NP uptake and CP pathways.

Main Results:

• Succinylchitosan-galactomannan (LSG) and succinylchitosan-PEG-chitosan (LSPC) NPs significantly induced IgG2a (CD8+ T-cell response).
• IgG1 (CD4+ T-cell response) was comparable across most NPs, except for hydrophobic succinyl-dodecyl-chitosan (LSD) NPs.
• LSG-NPs utilized a vacuolar CP pathway, while LSPC-NPs used the cytosolic CP pathway.

Conclusions:

• Nanoparticle engineering can modulate antigen cross-presentation pathways.
• Specific NP formulations (LSG and LSPC) are effective in inducing CD8+ T-cell responses.
• Understanding NP uptake mechanisms is vital for designing efficient immunogens.